How do oceanic plate movements cause earthquakes and tsunamis?

Oceanic plate movements are a major cause of earthquakes and tsunamis. These movements occur at the boundaries between plates, where tectonic activity is concentrated. There are three main types of plate boundaries: divergent, convergent, and transform. Each type of boundary has unique characteristics that influence the types of earthquakes and tsunamis that occur there.

Divergent plate boundaries are where two plates move away from each other. As they move apart, magma rises from the mantle to fill the space between them, creating new crust. Earthquakes at these boundaries are generally small and not very frequent, but they can still be felt. Tsunamis are not typically associated with divergent plate boundaries.

Convergent plate boundaries are where two plates move toward each other. There are three types of convergent boundaries: oceanic-continental, oceanic-oceanic, and continental-continental. At oceanic-continental boundaries, the denser oceanic plate subducts, or sinks, beneath the less dense continental plate. This can create deep-sea trenches and volcanic arcs, and is the source of some of the largest earthquakes and tsunamis on record. At oceanic-oceanic boundaries, the denser plate subducts beneath the less dense plate, creating island arcs and trenches. Earthquakes and tsunamis at these boundaries are less frequent but still significant. Continental-continental boundaries create mountains but are not usually associated with earthquakes or tsunamis.

Transform plate boundaries are where two plates slide past each other. These boundaries are associated with frequent, but less intense earthquakes. Tsunamis are not typically associated with transform boundaries.